1; RUN: opt -loop-idiom -mtriple=x86_64 -mcpu=core-avx2 < %s -S | FileCheck --check-prefix=ALL %s
2; RUN: opt -loop-idiom -mtriple=x86_64 -mcpu=corei7 < %s -S | FileCheck --check-prefix=ALL %s
3
4; Recognize CTTZ builtin pattern.
5; Here it will replace the loop -
6; assume builtin is always profitable.
7;
8; int cttz_zero_check(int n)
9; {
10;   int i = 0;
11;   while(n) {
12;     n <<= 1;
13;     i++;
14;   }
15;   return i;
16; }
17;
18; ALL-LABEL: @cttz_zero_check
19; ALL:       %0 = call i32 @llvm.cttz.i32(i32 %n, i1 true)
20; ALL-NEXT:  %1 = sub i32 32, %0
21;
22; Function Attrs: norecurse nounwind readnone uwtable
23define i32 @cttz_zero_check(i32 %n) {
24entry:
25  %tobool4 = icmp eq i32 %n, 0
26  br i1 %tobool4, label %while.end, label %while.body.preheader
27
28while.body.preheader:                             ; preds = %entry
29  br label %while.body
30
31while.body:                                       ; preds = %while.body.preheader, %while.body
32  %i.06 = phi i32 [ %inc, %while.body ], [ 0, %while.body.preheader ]
33  %n.addr.05 = phi i32 [ %shl, %while.body ], [ %n, %while.body.preheader ]
34  %shl = shl i32 %n.addr.05, 1
35  %inc = add nsw i32 %i.06, 1
36  %tobool = icmp eq i32 %shl, 0
37  br i1 %tobool, label %while.end.loopexit, label %while.body
38
39while.end.loopexit:                               ; preds = %while.body
40  br label %while.end
41
42while.end:                                        ; preds = %while.end.loopexit, %entry
43  %i.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.end.loopexit ]
44  ret i32 %i.0.lcssa
45}
46
47; Recognize CTTZ builtin pattern.
48; Here it will replace the loop -
49; assume builtin is always profitable.
50;
51; int cttz(int n)
52; {
53;   int i = 0;
54;   while(n <<= 1) {
55;     i++;
56;   }
57;   return i;
58; }
59;
60; ALL-LABEL: @cttz
61; ALL:      %0 = shl i32 %n, 1
62; ALL-NEXT: %1 = call i32 @llvm.cttz.i32(i32 %0, i1 false)
63; ALL-NEXT: %2 = sub i32 32, %1
64; ALL-NEXT: %3 = add i32 %2, 1
65;
66; Function Attrs: norecurse nounwind readnone uwtable
67define i32 @cttz(i32 %n) {
68entry:
69  br label %while.cond
70
71while.cond:                                       ; preds = %while.cond, %entry
72  %n.addr.0 = phi i32 [ %n, %entry ], [ %shl, %while.cond ]
73  %i.0 = phi i32 [ 0, %entry ], [ %inc, %while.cond ]
74  %shl = shl i32 %n.addr.0, 1
75  %tobool = icmp eq i32 %shl, 0
76  %inc = add nsw i32 %i.0, 1
77  br i1 %tobool, label %while.end, label %while.cond
78
79while.end:                                        ; preds = %while.cond
80  ret i32 %i.0
81}
82
83